Is Shearing and Oxidation happening at the same time?

[Patman]

Does that mean next time I should pour 4.5 quarts only?

No, still add whatever it takes to get it to the full point on the dipstick. A lot of service manuals will specify what the full oil capacity will be for a dry engine vs what it needs after an oil change.

My Corvette’s engine holds a total of 7 quarts but when I drain it I only get out 6 quarts.

 

[Motor oil rookie]

No, still add whatever it takes to get it to the full point on the dipstick. A lot of service manuals will specify what the full oil capacity will be for a dry engine vs what it needs after an oil change.

My Corvette’s engine holds a total of 7 quarts but when I drain it I only get out 6 quarts.

I see. Thank you.

 

[Motor oil rookie]

Yep, sometimes they are on, sometimes they are off, lol.

In 0W-20, the 20 part can shear and oxidize. What about the OW part? Can oxidation thicken the 0W part of the oil?

 

[Patman]

In 0W-20, the 20 part can shear and oxidize. What about the OW part? Can oxidation thicken the 0W part of the oil?

As an oil gets more mileage on it, the first number does change because it’s cold cranking ability will change. In some cases an oil that starts out as a 0w20 will finish off as a 5w20.

 

[Motor oil rookie]

As an oil gets more mileage on it, the first number does change because it’s cold cranking ability will change. In some cases an oil that starts out as a 0w20 will finish off as a 5w20.

That sucks

 

[Motor oil rookie]

As an oil gets more mileage on it, the first number does change because it’s cold cranking ability will change. In some cases an oil that starts out as a 0w20 will finish off as a 5w20.

Thanks for the heads up. So a 5W-30 will become a 10W-30, 10W-30 in a vehicle that calls for 0W-20. No way I will ever use 5W-30 in my Jeep.

 

[Pablo]

Thanks for the heads up. So a 5W-30 will become a 10W-30, 10W-30 in a vehicle that calls for 0W-20. No way I will ever use 5W-30 in my Jeep.

That's a really gross (large) generalization.

A good, decent base oil 5W-30 will not thicken in anything close to normal use to harm your Jeep engine.

Reading through this thread (and others over the years) - the impacts of so called "oxidative thickening" have been quite exaggerated by posters. While yes when in rare cases an oil thickens, of course the entire viscometric data shifts right. But it's not a huge shift, it's not asphalt. Let's just think of a good synthetic (PAO/Ester) 10W-30 for example - new - the cold flow would be just fine for anything where you live. The oil would pump right up and flow. So again, after reading through these threads, there are a lot more things to worry about.

 

[Patman]

Thanks for the heads up. So a 5W-30 will become a 10W-30, 10W-30 in a vehicle that calls for 0W-20. No way I will ever use 5W-30 in my Jeep.

It’s more of a concern if you are doing longer intervals like me (10k in my Civic), as it’s likely to retain close to its original cold cranking ability for the first 5k. Of course this will vary from one engine to the next and one oil to the next as a better quality base oil such as one containing some PAO will be better in this regard.

 

[buster]

Changes in oxidation value is something I never used to look at. Most of the UOA's on here are unfortunately from BS/Labs. I do like to watch changes in oxidation value from virgin to used. But it's important to look at everything and not just get hung up on one data point.

Dr. Roger Dale England, vice president, chief R&D officer, Valvoline, Inc., explains that the primary oil degradation routes are oxidation and nitration.

 

[buster]

Some more information:

"Testing for acid number and oxidation are gaining ground as more relevant indicators of engine oil service life than base number in North America. “A high acid number does not mean the engine oil has turned acidic,” he says. “Acid number increases due to reactions with oxidation and oil degradation compounds. Oxidation test results provide a reliable trending parameter that complements other engine oil service life testing well (see New API Categories and Service Life for HD Engine Oils).”

Doyle continues, “Historically, people relied on testing for base number as a key indicator ..... With the significant reduction in sulfur in fuel and engine oil, the relevancy of using base number as a key indicator for service life has been significantly reduced. Formulation requirements today are more concerned with oxidation stability and the ability to handle contaminants that enter the engine oil from recirculated exhaust gases. Today’s engine oils are more concerned with protection from degradation due to oxidation, better detergency and dispersancy.”

"In regard to oxidation performance, Dr. Alisdair Brown, R&D technical director, Afton Chemical Ltd., says there are many ways oxidation can be measured: from simple laboratory bench tests that can take a few minutes to expensive multi-cylinder engine tests lasting several days all the way to OEM field trials that can take two to three years to complete."

"Brown explains that the Sequence IIIH test assesses the extent of oxidation via viscosity increase of the lubricant and the Mack T-13 test, which takes 360 hours and uses roughly 20 gallons of engine oil, tracks oxidation throughout the test by monitoring the increase in oxidation products via infrared spectroscopy as well as any changes in the viscosity of the oil."

 

[OVERKILL]

Thanks for the heads up. So a 5W-30 will become a 10W-30, 10W-30 in a vehicle that calls for 0W-20. No way I will ever use 5W-30 in my Jeep.

*can*, not *will*.

There are other factors too (of course there are, right?! LOL). An oil with the main base being PAO will tend to maintain its cold temperature performance better than one that's based on Group III or Group II. The reason for this is that of the main base oils (PAO and hydrocracked/hydroprocessed), PAO is the only one with no wax in it.

What drives viscosity increase impacting cold cranking speed (CCS) and the ability to be pumped (MRV) is the formation of wax crystals in colder temperatures. These form rapidly once a certain temperature threshold is crossed. Formulators use PPD's (Pour Point Depressants) to drive down the point at which this occurs, which is how you can have an oil based on a 4cSt GTL base for example, pass the CCS and MRV testing for the 0W-xx Winter grade, even though the Pour Point for the base oil is considerably higher than the temperature those tests are performed at.

PAO, having no wax, is not dependent on PPD's (though some may be included in the final product to deal with the additive package and carrier oil(s)). This is why you see insanely low pour points for oils with PAO as the dominant base. This also means they are significantly less likely to experience a degradation in their Winter test performance to the point where they no longer pass it.

Oils are allowed to "slip" a Winter grade in service, as @Patman noted, but that doesn't mean they necessarily will. As also noted, OCI length is a factor here as well.

 

[Motor oil rookie]

*can*, not *will*.

There are other factors too (of course there are, right?! LOL). An oil with the main base being PAO will tend to maintain its cold temperature performance better than one that's based on Group III or Group II. The reason for this is that of the main base oils (PAO and hydrocracked/hydroprocessed), PAO is the only one with no wax in it.

What drives viscosity increase impacting cold cranking speed (CCS) and the ability to be pumped (MRV) is the formation of wax crystals in colder temperatures. These form rapidly once a certain temperature threshold is crossed. Formulators use PPD's (Pour Point Depressants) to drive down the point at which this occurs, which is how you can have an oil based on a 4cSt GTL base for example, pass the CCS and MRV testing for the 0W-xx Winter grade, even though the Pour Point for the base oil is considerably higher than the temperature those tests are performed at.

PAO, having no wax, is not dependent on PPD's (though some may be included in the final product to deal with the additive package and carrier oil(s)). This is why you see insanely low pour points for oils with PAO as the dominant base. This also means they are significantly less likely to experience a degradation in their Winter test performance to the point where they no longer pass it.

Oils are allowed to "slip" a Winter grade in service, as @Patman noted, but that doesn't mean they necessarily will. As also noted, OCI length is a factor here as well.

HPL SC 0W-20 has better pour point than Red Line 0W-20. Does it mean it has more of this PAO thingy?

 

[OVERKILL]

HPL SC 0W-20 has better pour point than Red Line 0W-20. Does it mean it has more of this PAO thingy?

View attachment 279064

View attachment 279066

Yeah, it probably has more PAO.

 

[Motor oil rookie]

Yeah, it probably has more PAO.

In the early rapid shearing, is it possible that the 5W gets sheared closer to 0W?

 

[OVERKILL]

In the early rapid shearing, is it possible that the 5W gets sheared closer to 0W?

The Winter grade isn't impacted by shear in the same way the SAE grade is because it's based on CCS/MRV performance.

 

[mr_boring]

My fellow human, you are in for a wild emotional ride if you don't look at all of this at the 30,000 foot view.

There are dozens of motor oils that will serve you well. HPL may very well be the best oil on this planet. If that's what you choose to use, do so. I mean, I have a favorite butter that to me tastes oh so good and I use a lot of it. It's about double what the almost as good other butters cost, but, I like it. I even tend to use it in dishes where store brand butter would be just as acceptable. Some people would say that I'm wasting it when I use it to make yeast rolls. I could save a dollar by using store brand to make them with and then slather the expensive stuff on and really get the full flavor that I pay 8 bucks a lb to taste, but most of the time I choose not to. Even though the $6/lb butter tastes great and the $4/lb butter is fine to cook with.

But good on you for asking good questions. You seem very intent on gleaning as much knowledge as you can. Knowledge is power.

Just don't get caught up in every single post or analysis on the internet. Your brain will explode. There are a few very knowledgeable people who post on the internet, and we are lucky to have a nice concentration of them on this site. We've also got a whole bunch of exshperts who kinda sorta know what they are talking about on a good day.

I glean a little nugget from this forum occasionally. But I gotta sift though an awful lot of useless material and tailings to find those nuggets.

EDIT: In my rambling way, I'm only trying to warn you about information overload. I was there once. I searched for the magic formula. Over time I realized that I wasn't looking at millions of data points that all point in a pretty singular direction. That there were and still are dozens of motor oils that will serve almost every engine very well. Pick your horse and ride it - pour the expensive stuff out every 4k if you choose to.

 

[Motor oil rookie]

The Winter grade isn't impacted by shear in the same way the SAE grade is because it's based on CCS/MRV performance.

Is there a driving habit that could accelerate that rapid initial shear? Like chew the 0W-30 from 10.0 to 9.0 with in a couple of hundreds of miles? Can crawling slowly offroad with 130 degrees oil temp for a couple of hours do that? Or driving at 90 mph for 3 hours in Nevada in the summer heat?

 

[OVERKILL]

Is there a driving habit that could accelerate that rapid initial shear? Like chew the 0W-30 from 10.0 to 9.0 with in a couple of hundreds of miles? Can crawling slowly offroad with 130 degrees oil temp for a couple of hours do that? Or driving at 90 mph for 3 hours in Nevada in the summer heat?

No. It's characteristics of the engine, usually one with a lot of timing chains will be harder on oil in terms of shear than one with a belt or smaller, shorter chains.

 

[Motor oil rookie]

No. It's characteristics of the engine, usually one with a lot of timing chains will be harder on oil in terms of shear than one with a belt or smaller, shorter chains.

I see. They say my Pentastar is very easy on oil. So it cannot do that. So I'm good with HPL Supercar 0W-20.
Can one buy a shearing machine?

 

[kschachn]

I see. They say my Pentastar is very easy on oil. So it cannot do that. So I'm good with HPL Supercar 0W-20.
Can one buy a shearing machine?

How long are you going keep this going?